Water → N-(tert-Butoxycarbonyl)-O-cyclopentyl-L-tyrosine

HRID 1589322Notes

Reaction equation

HRID 1589322 reaction equation
[C:1]([O:5][C:6]([NH:8][C@H:9]([C:18]([OH:20])=[O:19])[CH2:10][C:11]1[CH:16]=[CH:15][C:14]([OH:17])=[CH:13][CH:12]=1)=[O:7])([CH3:4])([CH3:3])[CH3:2].[H-].[Na+].[CH:23]1(Br)[CH2:27][CH2:26][CH2:25][CH2:24]1.O>CN(C=O)C.ClCCl>[C:1]([O:5][C:6]([NH:8][C@H:9]([C:18]([OH:20])=[O:19])[CH2:10][C:11]1[CH:12]=[CH:13][C:14]([O:17][CH:23]2[CH2:27][CH2:26][CH2:25][CH2:24]2)=[CH:15][CH:16]=1)=[O:7])([CH3:4])([CH3:2])[CH3:3]

Participants

7

Reactant 4

HCID 962WaterHCID 8728BromocyclopentaneHCID 24758Sodium hydrideHCID 117439L-Tyrosine, N-(1,1-dimethylethoxy)carbonyl-

Product 1

HCID 18601563N-(tert-Butoxycarbonyl)-O-cyclopentyl-L-tyrosineYield 50.5%

Reagents, catalysts & solvents 2

HCID 6228DimethylformamideSolventHCID 6344DichloromethaneSolvent

Procedure

To a cold (10°) stirred solution of N-tertiarybutoxycarbonyl-L-tyrosine (11.25 g, 40 mM) in dry DMF (150 ml) under argon was added sodium hydride (2.76 g, 80% dispersion in oil, 92 mM). After one hour at 10° cyclopentyl bromide (5.96 g, 40 mM) was added and the reaction was allowed to warm and stir to room temperature overnight. Water (200 ml) and dichloromethane (300 ml) were then added and the aqueous layer was separated. The separated aqueous layer was washed with dichloromethane, acidified with hydrochloric acid and re-extracted with dichloromethane (300 ml×2). These latter dichloromethane extracts were dried and concentrated in vacuo to an oil. Column chromatography of this material on silica eluting with ethyl acetate gave the title compound as a foam (7.05 g). This was used directly in the next step without further purification.

Workup

  1. temperatureto warm
  2. customthe aqueous layer was separated
  3. washThe separated aqueous layer was washed with dichloromethane
  4. extractionre-extracted with dichloromethane (300 ml×2)
  5. dry with materialThese latter dichloromethane extracts were dried
  6. concentrationconcentrated in vacuo to an oil

Sources & evidence

ORD record
ord-f4cc41d314e840c3968faa64ad0f7db1
Source dataset
uspto-grants-1986_02
Patent number
US04568666

Reaction notes

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